How To Choose The Material Of Slurry Pump

Nov 21, 2025

How to choose the material of slurry pump for different chemical media? People often have a misconception that stainless steel is a universal material that can handle any medium and environmental conditions. This is very risky, it can cause transaction disputes at the slightest and major accidents at the most. Below are several common chemical media and their material selection.

1. Hydrochloric acid

 

The vast majority of metal materials are not resistant to hydrochloric acid corrosion, including various stainless steel materials, when the concentration of hydrochloric acid is relatively high. Molybdenum containing high silicon iron can only be used for hydrochloric acid below 50 ℃ and 30%. Unlike metallic materials, the vast majority of non-metallic materials have good corrosion resistance to hydrochloric acid, so lined rubber pumps and plastic pumps (such as polypropylene, fluoroplastics, etc.) are the best choices for transporting hydrochloric acid.

2. Sulfuric acid

 

As one of the highly corrosive media, sulfuric acid is an important industrial raw material with a wide range of applications. The corrosion of materials varies greatly with different concentrations and temperatures of sulfuric acid. For concentrated sulfuric acid with a concentration above 80% and a temperature below 80 ℃, carbon steel and cast iron have good corrosion resistance, but they are not suitable for high-speed flowing sulfuric acid.

 

 

Therefore, carbon steel and cast iron are not suitable for pump valve materials; Even ordinary stainless steels such as 304 and 316 have limited use for sulfuric acid media. Therefore, pumps and valves for transporting sulfuric acid are usually made of high silicon cast iron or high alloy stainless steel, such as 20 alloy, ceramic pumps, but they are very difficult to cast and process. Fluoroplastics have good sulfuric acid resistance, and using fluorine lined pumps is a more economical choice.

3. Nitric acid

 

As a highly oxidizing acid, most metals are rapidly corroded and destroyed in nitric acid. At room temperature, fluoroplastics and stainless steel materials have strong corrosion resistance to nitric acid. It is worth noting that molybdenum containing stainless steel (such as 316, 316L) not only has no better corrosion resistance to nitric acid than ordinary stainless steel (such as 304, 321), but sometimes even inferior. For high-temperature nitric acid, titanium and titanium alloy materials are usually used.

4. Acetic acid

 

It is one of the most corrosive substances in organic acids. Ordinary steel will corrode severely in acetic acid at all concentrations and temperatures. Stainless steel is an excellent material resistant to acetic acid, and 316 stainless steel containing molybdenum can also be used for high temperatures and dilute acetic acid vapor. For high temperature and high concentration acetic acid or other corrosive media with strict requirements, high alloy stainless steel or fluoroplastic pumps can be selected.

5. Alkali

 

The common chemical alkali is sodium hydroxide. Sodium hydroxide solutions below 80 ℃ and with a concentration of 30% can be made of steel materials, and many factories still use ordinary steel at temperatures below 100 ℃ and 75%. Although corrosion increases, the economy is good.

The corrosion resistance of ordinary stainless steel to alkaline solution is not significantly better than that of cast iron, and it is not recommended to use stainless steel as long as a small amount of iron is allowed to be added to the medium. For high-temperature alkaline solutions, titanium and titanium alloys or high alloy stainless steel are commonly used. Generally, cast iron pumps can be used for low concentration alkaline solutions at room temperature.

For special requirements, various chemical fiberglass pumps, chemical plastic pumps, PTFE magnetic pumps, stainless steel magnetic pumps, fluoroplastic magnetic pumps, high-temperature resistant magnetic pumps, etc. can be used.

6. Ammonia (ammonia hydroxide)

 

Most metals and non metals have mild corrosion in liquid ammonia and ammonia water (ammonia hydroxide), only copper and copper alloys are not suitable for use.

 

7 Alcohols, ketones, esters, etc.

 

Common alcohols include methanol, ethanol, ethylene glycol, propanol, etc; Ketones such as acetone, butanone, etc; Esters such as methyl and ethyl esters are generally non corrosive and can be used as common materials, but stainless steel is the best choice for cleaning; Additionally, it is worth noting that ketones and esters have solubility in various types of rubber, so attention should be paid when selecting sealing materials.

7. Saltwater and seawater 

 

For media such as seawater, the corrosion rate of ordinary steel is not very high in sodium chloride solution, seawater, and saltwater, and generally requires coating protection; Various types of stainless steel also have low uniform corrosion rates, but may cause localized corrosion due to chloride ions. 316 stainless steel material is usually preferred.